[4 DOF Robot Arm Keyestudio][Lab 02][i-Duino UNO R3B] Each +/- 90 Degree Base Servo Speed Control

#include <Servo.h>
Servo myservo1;
int pos1 = 90;
void setup() {
  checkSW();
  myservo1.attach(A1);
  delay(3000);
}

void loop() {

  for(pos1;pos1>0;pos1--)
  {
    myservo1.write(pos1);
    delay(10);
  }
  delay(3000);
  for(pos1;pos1<90;pos1++)
  {
    myservo1.write(pos1);
    delay(10);
  }
  delay(3000);
  for(pos1;pos1<180;pos1++)
  {
    myservo1.write(pos1);
    delay(10);
  }
  delay(3000);
  for(pos1;pos1>90;pos1--)
  {
    myservo1.write(pos1);
    delay(10);
  }
  delay(3000);
}
void checkSW()
{
  pinMode(7, INPUT);
  while(!digitalRead(7)){

  }

}